During playback, you can switch the video resolution automatically or manually to accommodate different sizes of playback devices and network conditions, thus enhancing the viewing experience. This article will explain several scenarios.
Live Streaming
Live streaming videos are played in the form of URLs. When initializing the player, you can specify the URL to be played through the sources field. Alternatively, after initializing the player, you can play by calling the src method on the player instance.
1. Adaptive Bitrate (ABR)
Adaptive bitrate URLs can seamlessly transition during switches without causing interruptions or jumps, ensuring a smooth transition in both visual and auditory experiences. This technology is also relatively simple to use; you just need to pass the playback URL to the player, which will automatically parse the sub-streams and render the resolution switching component on the control bar.
Example 1: Playing HLS adaptive bitrate URLs
During the player's initialization, when an adaptive bitrate URL is passed in, the player will automatically generate a resolution switching component and switch automatically based on network conditions.
const player = TCPlayer('player-container-id', {
sources: [{
src: 'https://hls-abr-url',
}],
});
Note:
Parsing the substreams of an HLS adaptive bitrate requires the dependency on the MSE API of the playback environment. In browsers not supporting MSE (e.g., Safari on iOS), the browser internally handles this by automatically switching resolutions based on network conditions, but it won't be able to parse multiple resolutions for manual switching.
Example 2: Playing WebRTC adaptive bitrate URLs
In the WebRTC adaptive bitrate scenario, after the address is input, the player will automatically decompose the substream addresses based on the ABR template in the address.
const player = TCPlayer('player-container-id',{
sources: [{
src: 'webrtc://global-lebtest-play.myqcloud.com/live/lebtest?txSecret=f22a813b284137ed10d3259a7b5c224b&txTime=69f1eb8c&tabr_bitrates=d1080p,d540p,d360p&tabr_start_bitrate=d1080p&tabr_control=auto'
}],
webrtcConfig: {
enableAbr: true,
abrLabels: {
d1080p: 'FHD',
d540p: 'HD',
d360p: 'SD',
auto: 'AUTO',
},
},
});
The following explanations are provided for the parameters in the WebRTC URL:
1. tabr_bitrates specifies the ABR template, and the number of templates will determine the number of rendered resolutions. If no separate resolution label is set, the template name (e.g., d1080p) will be used as the name of the resolution.
2. tabr_start_bitrate specifies the initial resolution setting.
3. tabr_control sets whether automatic resolution switching is enabled. Once enabled, the player will render an option for automatic resolution.
2. Manually setting the resolution
If the playback URL is not an adaptive bitrate URL, you can also manually set the resolution. See the following code:
const player = TCPlayer('player-container-id', {
multiResolution:{
sources:{
'SD':[{
src: 'http://video-sd-url',
}],
'HD':[{
src: 'http://video-hd-url',
}],
'FHD':[{
src: 'http://video-fhd-url',
}]
},
labels:{
'SD':'Standard Definition','HD':'High Definition','FHD':'Full High Definition'
},
showOrder:['SD','HD','FHD'],
defaultRes: 'SD',
},
});
VOD Scenario
In the VOD scenario, if you play via fileID, which type of file to play (source file, transcoded file, adaptive bitrate file) and the resolution of substreams of the adaptive bitrate file are all set in the player signature. You can refer to the guide Play back an adaptive bitrate streaming video to understand the entire process of playing videos in the VOD scenario. When calculating the player signature, you can set the display names of substreams of different resolutions through the resolutionNames in the contentInfo field. If you leave it blank or fill in an empty array, the default configuration is used. resolutionNames: [{
MinEdgeLength: 240,
Name: '240P',
}, {
MinEdgeLength: 480,
Name: '480P',
}, {
MinEdgeLength: 720,
Name: '720P',
}, {
MinEdgeLength: 1080,
Name: '1080P',
}, {
MinEdgeLength: 1440,
Name: '2K',
}, {
MinEdgeLength: 2160,
Name: '4K',
}, {
MinEdgeLength: 4320,
Name: '8K',
}]
The number of substreams during playback depends on the number of substreams converted according to different adaptive bitrate templates during transcoding. These substreams will fall within the MinEdgeLength range set by resolutionNames based on short side length and then be displayed with the corresponding Name as the clarity name.